I'm not really sure, but it would seem to me, that it would be better to gather cooler air from the floor to send back to the stove.

With that said, with reference to a cathedral ceiling, it would probably be beneficial to bring some of the warmest air from the ceiling back down to "living height".

edit:

Adamiscold wrote:Would having a return duct near the top of a cathedral ceiling work for this type of setup? I know I see more and more systems having the return air ducts closer to the ceiling where it can get the warmer air to return back to the furnace, but would this be ideal for a coal stove set up or should the return be placed in the floor instead?

Heat transfer is always most efficient when the temperature differential is the greatest. So, it would be more efficient to send the coolest air in the house back to the stove for reheating.

What I believe he is talking about are return ducts that are installed higher up for a Heating/Air Conditioning System. The house we live in has 14 foot ceilings upstairs with a furnace in the attic.I did a ton of research to ascertain if this is a correct setup.It actually is correct and does work quite well with the furnace provided the ducts are well insulated. It works super for A/C because the cold air drizzles down through the heated air which is rising to the returns. We have a large ceiling fan which runs pushing down for summer and pulling up for winter.This improved the living room heating stove air circulation by alot!Now before you elaborate and say that the furnace is in the basement with hot air registers at floor level and cold air returns at ceiling hieght. There is logic for that too. By putting both registers at floor level across the room from each other. You will feel a cold draft across your feet and legs every time the furnace cycles. By putting the cold air returns higher up then the heated air is continously rolling forward and up as it heats "all" the air in the room till it reaches the far wall as lukewarm air and is returned to the furnace for reheating.My downstairs furnace works exactly in this way. My coal/wood stove is down there in the Family Room where I have cut a hole in the ceiling to allow air to rise up to the second floor hallway. It gets too warm downstairs but allows the upstairs to be more comfortable at that end of the house which is at the opposite end of the house from the Living Room stove.

I have to say that I think if it's taking the warm air from the ceiling and sending it back to be reheated at the stove, wouldn't the air coming out of the floor vent be warmer then it normally would because it has been preheated? If it works for water wouldn't it also work for air? Wouldn't that in some way make the heating system a little more efficient?

I have to say that I think if it's taking the warm air from the ceiling and sending it back to be reheated at the stove, wouldn't the air coming out of the floor vent be warmer then it normally would because it has been preheated? If it works for water wouldn't it also work for air? Wouldn't that in some way make the heating system a little more efficient?

The air might be a little warmer, if you started with pre-heated air. But the temperature rise (difference) between the input and output wouldn't be as great, as it would be between cold input and warm/hot output. In other words the temperature gain would be greater with a cold air input, thus the stove would be working more efficiently, as more heat would be removed from it. Once you get your fire established, think of what you have to do, to keep it the coolest (remove the most heat) ... run hot air through it? run the air through it very slowly? or run cold/cool air through it at a moderate rate?

The other scenario by "drujinin" is referring to "comfort", rather than efficiency.

The same principles apply to liquids, as well as air. To get the most efficiency from the stove, you need to get the most heat transferred out of it for the amount of air that is flowing over/through it, for a given period of time.

YEP! Its strictly cmfort f the people in the house as far as HVAC goes. The initial statements were made the guy said I haveseen houses where the cold air returns are up high on a ceiling and he wanted to know why. So as far as Heating and Ventilation. That is the answer I gave.NOW on to the stoves. The ceiling fan in the living room pulls up from the middle of the room and pushes the warm air down the walls in winter to creat a warming effect. Even the fan manufacturers state this! Consequently this is what circulates stove air in our kitchen, dining room and living room. Its the bedrooms in the far end of the house when you wake up in the morning and your bedrom is 46F! I cut the hole in the hall floor to allow air to both pass up and push cold air down the stairs. At the same token air reverses and comes down the hole allowing air at the stairs to mix with warm air up stairs and move toward the bedrooms.Honest it works! Use a smoking tia stick to follow the air currents.

I would imagine for HVAC the returns half way up is a compromise. I would guess, for most efficiency, the heating return should be near the floor and the A/C return toward the ceiling. ??? ... rather than that, they utilize one in the middle.

See part of my thinking was I could use the high return duct in the summer to help circulate the cool air through out the house. Having a return in the middle just wont work for me, no room for it. Maybe I'll try using one feed duck off to our addition/sun room and see how well the open stairs work for returning the air back to the basement? I know last year there was mixed air on the stairs some cool air mixed in with the warm air in different spots.

I have been in several Ranch homes where the furnace is in the basement, they have the heating ducts near the floor with the cold air returns near the floor. But you look up the same wall and directly above the cold air return near the ceiling is an A/C return. Close the door on the cold air return and it will suck from the high grill. The only problem is you need a good furnace with a multi-speed motor to make this system work.As far as the mixed air on the stairs, putting anoth hole between those 2 floors opposite the stairs will break that Thermal Barrier and allow the air to move either up or down. At least I BELIEVE mine works better.

I believe every situation is different. Different things have to be evaluated and tried. Since most situations are "retrofit", certain limitations will be encountered (where can you, or want to, put a hole in the floor, wall or ceiling. Where can you run ducts, etc.) . Some will work and some won't. You may have to wait until heating season, to see where it's too hot or too cold and then try to figure out what needs to be done to help.

It's kind of raining here on and off, so ... guess what? You get pictures of my latest project!

As I mentioned earlier, I want to put two modified oil tanks in the basement for coal bins. I've got one cut and in the basement, but haven't acquired the second one, yet. Pictures of that will come later.

So, this phase of the project is fabricating the coal chute and installing it. I started with some fairly heavy gauge 10" round stainless steel stove pipe. It didn't seem like the "round" pipe was going to be the best, as I was limited to space with the 2' thick field stone foundation and ceiling height, etc.. Rectangular seemed to better adapt itself. The 10" round became a 6" x 10" rectangular. Also, I put an angled piece on the 4' length to bring it up out of the brick patio, so that it didn't extend out so far. I would have liked to have gotten it a bit steeper, but didn't have the room. I used S.S. pop rivets to join the two pieces of pipe and make the lid. The pipe itself was factory welded at the seam. The chute was inserted in an old window well area, which had been closed up with block, brick, stone and mud.

It may not seem too large in size, but if I'm shoveling the coal by hand, I think, it will handle it! I've got another chute from the truck, which I made of a piece of galvanized metal roofing, with the sides folded up.

I hadn't planned on anything over it for the winter ... maybe a plastic mud bucket. It's right next to the back door and close to the drive, so it will be clear in any case. Hopefully, I won't need any more coal through the worst part of the winter.

This is the first of the stove modification to get more ash capacity. I really, don't expect many of you to go through this.

I got the stove "detached from the house". Since it was one of those days, when nobody was around, I had to use my '53 Ford Jubilee for the grunt work. I used the come-a-long to bring it up the steps and then lifted it and away I went. It was probably the easiest and safest method.

In the two lower pictures, you can see part of the problem for the limited ash capacity ... while the ash door frame is 4" high, only part of it is open, due to the structure behind it and the grates, which hang down behind that. Thus, an ash pan of only 3" in height will fit in the hole.

I've bisected the stove, right above the floor (pictures to follow). A 1" insert between top and bottom, would allow the full 4" of door frame to be used and the original ash door, but I think, I'll go for a little more (to be determined).